Photographic film tends to be processed in a single strip once the film has been removed from its cassette. Strips of negative film are processed by transporting them, either as a single individual strip or as a continuous length comprising two or more strips of shorter lengths, through a series of processing solutions in various tanks in the processing apparatus.
In known processing apparatus;, the film strip is pulled through tanks containing the processing solutions either by a leader which is attached to the leading edge of the film strip, or by moving a rack or spiral containing the film strip from tank to tank. Individual film strips may be pre-spliced into a long reel with a leader card at the front end, clipped to a rack, or fed into a spiral.
Where the film strip is attached to a leader, it is unloaded from the cassette and attached to the leader in a manual operation. The leader is then fed into the processing apparatus so that the film can be processed as it is transported through the apparatus.
It is well known to guide film or other photographic material through the apparatus by pushing or pulling the material through grooves formed in side walls of processing racks. These grooves are machined in the side walls and therefore have a fixed position relative to the processing rack.
In the arrangement described above, the grooves may collect dirt and debris which may eventually build up to such an extent that the material being processed cannot easily be transported during processing and may become damaged. Furthermore, if the material being processed is damaged along its edges, the positive location in the grooves as the material is drawn through the processing apparatus may be lost causing the material to jam. This causes problems for an operator who then has to strip the appropriate rack and remove the material causing the jam.
EP-A-0 168 690 discloses a guiding device for use in copying apparatus. This device comprises a lower plate and an upper plate each of which have a plurality of dependent portions, the plates being arranged so that the dependent portions of each plate face each other and are aligned to define a path for movement of the copying paper. The plates lie parallel to the direction of travel of the paper through the copying apparatus, and the dependent portions allow the copying paper to be guided across its entire surface as it travels through the apparatus.
However, in photographic processing apparatus, the widths of material involved are considerably less than that utilized in copying apparatus. As a result, there is no need for the material to be guided across its entire surface. Furthermore, photographic material, film or paper, is inherently stiffer than copying paper and it is possible to guide the material solely at its edges in most instances.
It is therefore an object of the present invention to provide a guiding arrangement for photographic processing apparatus in which guide plates are used both to define a path through the apparatus for the material being processed and to guide the material as it passes through the processing apparatus.